U. of Bath distributes DC to power library PCs

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CA_Steve
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U. of Bath distributes DC to power library PCs

Post by CA_Steve » Wed Mar 23, 2011 7:22 am

Article via Slashdot.
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djkest
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Re: U. of Bath distributes DC to power library PCs

Post by djkest » Tue Apr 19, 2011 1:56 pm

That's cool but...

How much did it cost?
How efficient is it?
How long before the "break even" point?

If they really wanted to be green, they should have used photovoltaic solar panels to create DC electricity to feed the computers when they are used most- during the day. They are still doing AC to DC conversion- just using a large centralized piece of equipment.

I have a sneaky feeling that they aren't going to save any money on this, they are just going to get publicity.

Also, knowing a little bit about electrical engineering, the 12V DC power would have greater transmission losses than 240V AC.

CA_Steve
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Re: U. of Bath distributes DC to power library PCs

Post by CA_Steve » Tue Apr 19, 2011 3:11 pm

2 points.

1) This is the UK. How much solar energy do you think they get as compared to, say, Colorado :D
2) Screw "green". I just thought it was interesting to see somebody other than a server farm working on DC distribution. Will this implementation be the best possible? I doubt it. But, it should hopefully lead to some insights on what could be done better; The cycles of learning thing.
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Dirge
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Re: U. of Bath distributes DC to power library PCs

Post by Dirge » Mon Jun 13, 2011 7:32 pm

I am all for new approaches to lowering the use of power in servers and large networks. Additionally saving all that heat in a server room would be super. Since using DC is more dangerous than AC I wonder if they can safely implement this in a home environment.

multiplexer
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Re: U. of Bath distributes DC to power library PCs

Post by multiplexer » Fri Jul 15, 2011 10:02 am

I'm pretty sure they will save money as long as they didn't spend an absolute fortune on it. One big central ac-dc converter can improve (quite massively) power factor and efficiency and reduce the total cost significantly. Big power converters are much easier to make 95+ % efficient with near-perfect power factor than lots of small ones. Also, a significant proportion of heat dissipation is removed from the computers themselves. The only downside to low-voltage DC distribution is ohmic losses, so they need to compensate via thicker wires. Then again, DC doesn't suffer from skin effect and the total power to be distributed is probably a good 30% lower (because of the ac-dc efficiency), which negates actually quite a bit of this effect.

Seems pretty solid from an engineering point of view.

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